Mechanical function control of continuously variable transmission hydraulic system

ABSTRACT

A simplified continuously variable transmission system control provides a variable clamping force and a differential cylinder pressure manipulation to change sheave ratios. The system control uses two pumps. The first pump provides the variable clamping force. The second pump provides pressure changes to effect ratio changes. The clamping force can be varied based upon operator demand on an associated engine.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/126,586, filed May 23, 2008, which claims the benefit under 35 U.S.C.§119(e) of U.S. Provisional Patent Application No. 60/939,808, filed onMay 23, 2007, which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to simplified electronic-freecontinuously variable transmission (CVT) control arrangements thatcontrol pressurizing and providing variable pressure control of ahydraulic system in a belt or chain drive CVT.

2. Description of the Related Art

A typical vehicle CVT comprises two V shaped pulleys and a steel chainor belt disposed between them. The chain or belt transfers power fromone pulley to the other pulley during pulley rotation. Both pulleys arecapable of axial displacement of a belt track in order to change theratio of the vehicle drive line. The pulleys usually are hydraulicallyactuated for ratio changing by integral hydraulic cylinders, which alsosupply a variable clamping force on the chain. The clamping force ismodulated, depending on the torque load, to reduce the likelihood ofchain slippage under high torque conditions but without applyingunnecessary force that would increase the chain wear at low torqueconditions.

Many CVT control systems are in existence and in use around the worldthat satisfy the above-described functions. These generally arecomputer-controlled systems that gather information from engine anddriveline sensors, including the driver actuated throttle position. Thisinformation is used to control the ratio changing and chain clampingforces by selective manipulation of the hydraulic system pressures.These systems are complex and feature many components that increase thecost of manufacture.

SUMMARY OF THE INVENTION

A simplified construction capable of performing these functions isdesired. The methods of pressurizing and control to be described hereapply to two separate functions. The first function is for the variablesystem pressure control for chain clamping and other use. The secondfunction is for the differential cylinder pressure manipulation thatchanges the CVT engine/drive line ratios.

In some configurations, a transmission and transmission controlcomprises a continuously variable transmission. The continuouslyvariable transmission comprises a first sheave and a second sheave. Aflexible member connects the second sheave to the first sheave such thatrotation of the first sheave causes rotation of the second sheave. Acontinuously variable transmission output shaft is connected to thesecond sheave. A planetary transmission comprises an input shaft. Theinput shaft of the planetary transmission is connected for rotation withthe continuously variable transmission output shaft. The planetarytransmission input shaft is connected to a planetary transmission outputshaft. A motor drives a first pump and a second pump. The first pump isfluidly connected to the first sheave and the second sheave. The firstpump also is fluidly connected to a pressure relief valve. The pressurerelief valve is connected to a flexible member lubrication conduit suchthat bypass flow from the pressure relief valve can be directed to theflexible member of the continuously variable transmission. The secondpump is fluidly connected to a valve. The valve is selectively fluidlyconnected to the first sheave and the second sheave such that fluid canbe supplied through the valve to the first and second sheave to effectratio changes. The second pump comprises a pump case drain. The pumpcase drain is fluidly connected to the planetary transmission to supplyfluid to gears of the planetary transmission.

In some configurations, a transmission and transmission controlcomprises a continuously variable transmission. The continuouslyvariable transmission comprises a first sheave and a second sheave. Aflexible member connects the second sheave to the first sheave such thatrotation of the first sheave causes rotation of the second sheave. Acontinuously variable transmission output shaft is connected to thesecond sheave. A planetary transmission comprises an input shaft. Theinput shaft of the planetary transmission is connected for rotation withthe continuously variable transmission output shaft. The planetarytransmission input shaft is connected to a planetary transmission outputshaft. A first pump supplies fluid to the first sheave and the secondsheave such that the first pump creates a base clamping pressure. Meansfor modulating pressure according to engine demand is connected to thefirst pump such that increased operator demand on an engine results inhigher clamping pressures being applied to the first and second sheave.A second pump is fluidly connected to a valve. The valve selectivelyshifts fluid to at least one of the first and second sheaves to effectratio changes between the first and second sheaves.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of certain embodimentsof the present invention will be described with reference to drawings ofthose embodiments.

FIG. 1 is a schematic representation of a CVT system controlconfiguration that is arranged and configured in accordance with certainfeatures, aspects and advantages of the present invention.

FIG. 2 is a sectioned view of a relief valve that mechanically adjusts abypass flow to adjust clamping forces in the CVT.

FIG. 3 is a sectioned view of another relief valve that mechanicallyadjusts a bypass flow to adjust clamping forces in the CVT.

FIG. 4 is an illustration of a four-way valve used in the controlconfiguration of FIG. 1.

FIG. 5 is a schematic representation of a CVT system controlconfiguration that is arranged and configured in accordance with certainfeatures, aspects and advantages of the present invention.

FIG. 6 is a schematic representation of a CVT system controlconfiguration that is arranged and configured in accordance with certainfeatures, aspects and advantages of the present invention.

FIG. 7 is a schematic representation of a CVT system controlconfiguration that is arranged and configured in accordance with certainfeatures, aspects and advantages of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates a CVT system control 100 is illustrated. Theillustrated system control 100 provides a simplified and preferablysubstantially electronic free method of pressurizing and providingvariable pressure control of a hydraulic system in a belt or chain drivecontinuously variable transmission. In the illustrated system control100, two separate functions are controlled: chain clamping and cylinderpressure manipulation. The cylinder pressure manipulation changes CVTengine/drive line ratios when fluid passes from in either directionbetween cylinders.

In the illustrated configuration, an engine 102 has an output shaft thatdrives a continuously variable transmission (CVT) 104 through a torqueconverter 106. The CVT 104 comprises a primary sheave 110 and asecondary sheave 112. A flexible member 114, such as a belt or a chain,for example, connects the primary sheave 110 and the secondary sheave112. The secondary sheave 112 preferably drives an output shaft 116through a planetary transmission 120. The planetary transmission 120 canprovide functions such as low gear, reverse gear and parking. Otherconfigurations are possible.

The illustrated system 100 uses a single motor 122 to power componentsof the control system 100. The motor 122 preferably is an electric motorthat drives two separate pumps 124, 126. The motor 122 also preferablyreceives power from a 12 volt power source 130. While the power source130 can be a 12 volt power source, in some embodiments the power source130 can be a 40 volt power source or some other voltage power source.Moreover, other types of motors can be used.

The two pumps 124, 126 preferably comprise the first pump 124, whichcontrols chain clamping, and the second pump 126, which controlscylinder pressure manipulation to effect drive ratio changes. The pumps124, 126 can be vane pumps, gear pumps, or any other suitable pump thatcan draw oil from a reservoir 132. Preferably, the pumps 124, 126 arepositive displacement pumps.

As illustrated, the first pump 124 is driven by the motor 122. The firstpump 124 draws fluid from the reservoir 132. In the illustratedconfiguration, the first pump 124 is connected to the reservoir 132through a heat exchanger 134. Thus, fluid is drawn from the reservoir132, through the heat exchanger 134 and into the first pump 124.

Fluid flowing out from the first pump 124 is supplied to a passage 136that connects cylinders 140 of the primary sheave 110 to cylinders 142of the secondary sheave 112. The pressurized fluid within the passage136 establishes a base clamping force for both of the sheaves 110, 112.In order to establish and generally maintain a desired pressure withinthe passage 136, a pressure relief valve 144 can be fluidly connected tothe passage 136.

In some embodiments, the pressure relief valve 144 is a spring-loadedrelief valve. The pressure relief valve 144 can bypass excess pump flowto a lubrication passage 146. The flow through the lubrication passage146 can be directed onto the flexible member 114 of the CVT 104.

In addition to the bypass flow from the pressure relief valve 144,internal leakage from the first pump 124 can be directed into thelubrication passage 146. For example, a case return from the first pump124 can be connected to the lubrication passage 146 through an auxiliarypassage 150. Fluid used to lubricate the flexible member 114 of the CVT104 returns to the reservoir 132.

From the reservoir 132, the fluid is drawn through a first suctionpassage 152 into the heat exchanger 134. The fluid is further drawnthrough a second suction passage 154, which preferably fluidly connectsthe heat exchanger 134 to a suction port of the pump 124.

As discussed above, the pump 124 supplies fluid to the cylinders 140,142 to provide the base clamping force. The pump 124 preferably suppliesthe fluid through supply line 156, which connects to the passage 136that connects the cylinders 140 of the primary sheave 110 to thecylinders 142 of the secondary sheave 112. Desirably, the clamping forceis adjustable depending upon operator demands. Thus, the pressure reliefvalve 144 helps to adjust the pressure within the system, whereby theclamping force can be adjusted.

FIG. 2 illustrates an embodiment of the relief valve 144. Theillustrated relief valve 144 comprises a valve portion 202 and anadjustment portion 204. The adjustment portion 204 advantageously isconnected (e.g., mechanically connected) to the valve portion 202 suchthat the adjustment portion 204 can adjust the valve portion 202 inmanners that will be described.

The valve portion 202 comprises an inlet port 206. A valve body 210 isfluidly connected to the inlet port 206. The valve body 210 can be athreaded insert that can be positioned in a passage that is fluidlyconnected to the inlet port 206. Other configurations are possible.

The valve body 210 preferably comprises a through passage 212. An upperportion of the valve body 210 can comprise a valve seat 214. The valveseat 214 can be a tapered surface or the like. An outlet port 216fluidly connects to the through passage 212 with the valve seat beingpositioned between the inlet port 206 and the outlet port 216. In someconstructions, the outlet port 216 connects to the lubrication passage146, which provides a bypass outlet.

A lower and/or outer surface of a valve member 220 can rest against thevalve seat 214. In some configurations, the valve member 220 comprisesan outer surface that is tapered and that can interface with the valveseat 214. In some configurations, the tapering of the outer surface ofthe valve member 220 is different from the tapering of the correspondingsurface of the valve seat 214. The valve member 220 can affect flowbetween the inlet port 206 and the outlet port 216.

A bushing 222 abuts an upper end of the valve member 220 and preferablyis mounted on a stem 224 of the illustrated valve member 220. Thebushing 222 can provide an enlarged surface that can slide along aninner surface of a sleeve 226. The sleeve 226 can thread into a boreformed in the valve portion, for example.

In some configurations, an interface between the sleeve 226 and thesurrounding body can be sealed, such as with an o-ring 230 or the like.Similarly, an interface between the sleeve 226 and the stem 224 can besealed, such as with an o-ring 232 or the like.

A spring 234 or other suitable biasing member can be positioned betweenthe bushing 222 and a portion of the sleeve 226, for example, such thatthe valve member 220 is biased toward the valve seat 214. The biasingforce of the spring 234 establishes a base line pressure between thevalve seat 214 and the valve member 220.

The stem 224 is connected to the adjustment portion 204. In particular,the stem 224 preferably is connected to a diaphragm member 240. Thediaphragm member 240 preferably separates a chamber 242 into an intakeside 244 and a vent or ambient side 246. The vent side 246 comprises oneor more vent ports 250 that place the chamber 242 in fluid communicationwith the ambient air pressure while the intake side 244 preferablycomprises one or more ports 252 such that the intake side 244 is influid communication with an air intake system of the associated engine.

With a spark-ignited gasoline engine, for example, the air intakemanifold pressure is at high vacuum at idle and low power conditions.Under these conditions, the diaphragm member 240 exerts a strong pullforce on the stem 224 to reduce the biasing force from the spring 234.Thus, the clamping force is reduced at idle because of the increasedbypass flow. In other words, in the illustrated configuration, as thepressure in the intake system decreases, the stem 224 is pulled upwardtoward the intake side 244 of the chamber 242. Moving the stem 224 inthis direction moves the valve member 220 further away from the valveseat 214, which increases the bypass flow, which in turn reduces theoutput pressure experienced in the passage 136 from the output of thefirst pump 124. Stated another way, operation of the valve member 220can be influenced by changes in the intake manifold pressure andoperation of the valve member 220 influences the output pressureexperienced in the passage 236. Other configurations also are possible.

The configuration described above is a relatively simple and practicalsolution to controlling clamping pressures when compared to thecomplexities of a typical computer controlled system. The illustratedconfiguration is completely mechanical and automatic. The illustratedconfiguration requires no sensor inputs or electronics. Rather, theillustrated configuration simply uses a direct fluid connection from thechamber 242 to the intake manifold of the spark-ignited engine.

In addition to supplying clamping pressure, and in addition tolubricating the flexible member 114 through the bypass flow, the firstpump 124 also can supply lubrication to pulley bearings used in the CVT104. In some configurations, the bearings can be lubricated by providingcontrolled leakage that escapes at each end of shaft labyrinth seals orthe like external to the tubes that supply the pulley cylinders 140,142. Such a flow of fluid can be about 50 cc/minute maximum for each ofthe four bearings at the highest required clamping force and oiltemperature.

With reference now to FIG. 3, another embodiment of the relief valve 144is illustrated therein. The illustrated relief valve 144 of FIG. 3 canbe used with various types of engines. In some configurations, therelief valve 144 of FIG. 3 is used with a diesel engine. In particular,diesel powered vehicles use the relief valve 144 shown in FIG. 3 becausethe intake manifold pressure characteristics used with the relief valve144 shown in FIG. 2 generally are not compatible with a diesel engine.

The relief valve 144 illustrated in FIG. 3 comprises a valve portion 302and an adjustment portion 304. The adjustment portion 304 advantageouslyis connected (e.g., mechanically connected) to the valve portion 302such that the adjustment portion 304 can adjust the valve portion 302 inmanners that will be described.

The valve portion 302 comprises an inlet port 306. A valve body 310 isfluidly connected to the inlet port 306. The valve body 310 can be athreaded insert that can be positioned in a passage that is fluidlyconnected to the inlet port 306. Other configurations are possible.

The valve body 310 preferably comprises a through passage 312. An upperportion of the illustrated valve body 310 can comprise a valve seat 314.The valve seat 314 can be a tapered surface or the like. An outlet port316 fluidly connects to the through passage 312. In some constructions,the outlet port 316 connects to the lubrication passage 146, whichprovides a bypass outlet.

A lower and/or outer surface of a valve member 320 can rest against thevalve seat 314. In some configurations, the valve member 320 comprisesan outer surface that is tapered and that can interface with the valveseat 314. In some configurations, the tapering of the outer surface ofthe valve member 320 is different from the tapering of the correspondingsurface of the valve seat 314. The valve member 320 and the valve seat314 can alter flow through the pressure relief valve 144.

A bushing 322 abuts an upper end of the valve member 320 and preferablyis mounted on a stem 324 of the illustrated valve member 320. Thebushing 322 can provide an enlarged surface that can slide along aninner surface of a sleeve 326. The sleeve 326 can thread into a boreformed in the valve portion, for example.

In some configurations, an interface between the sleeve 326 and thesurrounding body can be sealed, such as with an o-ring 330 or the like.Similarly, an interface between the sleeve 326 and the stem 324 can besealed, such as with an o-ring 332 or the like.

A spring 334 or other suitable biasing member can be positioned betweenthe bushing 322 and a portion of the sleeve 326, for example, such thatthe valve member 320 is biased toward the valve seat 314. The biasingforce of the spring 334 establishes a base pressure between the valveseat 314 and the valve member 320.

The stem 324 is connected to the adjustment portion 304. In particular,the stem 324 preferably is connected to an input member 340. The inputmember 340 can comprise a push rod in some embodiments. The illustratedinput member 340 comprises a threaded hole 341 and a flange 343. Theflange can comprise a stepped lower surface in some embodiments.

The input member 340 preferably is connected to the throttle linkage orthe foot pedal, for example. More preferably, the input member 340 isoperatively associated with the throttle linkage, the foot pedal, boththe throttle linkage and the foot pedal or some component that operatesunder the influence of the foot pedal or the throttle linkage. In someconfigurations, a remotely operated component can be used while otherconfigurations use a direct coupling. The threaded hole 341 in theillustrated construction provides a connection to the foot pedal.

In any event, the input member 340 preferably is positioned at leastpartially within the adjustment portion 304. The stepped flange 343 ofthe illustrated input member 340 bears against a spring 342 or otherbiasing member. The stepped portion of the flange 343 can help keep thespring 342 properly positioned. The spring 342 also bears against aninsert 344 such that the spring 342 pushes the input member 340 and theinsert 344 away from each other but allows the movement (e.g., downwardmovement) of the input member 340 to cause movement (e.g., downwardmovement) of the insert 344. The insert 344 bears against the stem 324in the illustrated configuration.

Thus, movement of the input member 340 in a downward direction causescompression of the spring 342, which causes the insert 344 to movedownward against the stem 324. The movement of the insert 344 in turncauses movement of the stem 324, which increases the force applied tothe valve member 320 in a closing direction. In other words, in someconfigurations, operation of the foot throttle starts the compression ofthe spring 342, which in turn applies more force through the stem 324,hence increasing the output bypass pressure of the pump, which therebyraises the clamping force on the CVT sheaves. The motions describedabove progressively increase the force up to the full throttle position.At the full throttle position, which results in the maximum chainclamping force, the input member 340 reaches a stop 350 to reduce thelikelihood of the clamping force exceeding a predetermined limit.

While the configuration shown in FIG. 3 has been described in thecontext of a diesel engine, the configuration also can be used with agasoline spark-ignition engine, electric motor or other suitable motiveforce components.

With reference again to FIG. 1, the second pump 126 is used to controlratio changes in the illustrated CVT 104. As shown, output from the pump126 is supplied to a valve 400 through a supply line 402. In someconfigurations, the valve 400 can be a four-way open center valve (seeFIG. 4). Other configurations are possible.

The valve 400 connects to the passage 136, which preferably is ahigh-pressure line, that connects the cylinders 140, 142 by means of thetwo cylinder ports identified as 1 and 3 on FIG. 4. Preferably, thesecond pump 126 operates constantly. Flow through the valve 400 can bebi-directional by manipulation of the valve operating lever 401 in aclockwise or counterclockwise motion, which produces cylinder tocylinder 140-142 flow resulting in sheave travel and, hence, ratiochange. When the valve operating lever 401 is in the center position, asshown in FIG. 1, all of the four ports are open to each other forinterflow (i.e., the open center definition). In this position, the pump126 simply recirculates its full flow back to the pump inlet throughports 4 and 2 in FIG. 4 and creates no differential pressure between theCVT cylinders 140-142 in the passage 136, which is always under highpressure from the clamping pump 124, and pressurizes the passages toboth ports of the pump 126. Preferably, pump internal leakage is routedthrough a planetary hydraulic supply line 405 from a case drain port tothe planetary unit 120 for gear lubrication.

Since the pressure used to actuate the planetary functions is lower(e.g., about 200 psi) than the pressure used for CVT clamping forces(e.g., up to about 600 psi), a pressure reduction valve 406 can beinserted in the planetary hydraulic supply line 405 to reduce thelikelihood of overpressurization. In some configurations, a hydraulicaccumulator 408 is positioned between the pressure reduction valve 406and the planetary unit 120 to accommodate an increased demand inhydraulic flow such as might be encountered in a shift sequence. Suchconfigurations reduce the likelihood of momentary drops in CVT linepressure. In some configurations, the fluid from the hydraulicaccumulator 408 passes to a shift selection valve 409. In someconfigurations, it may be desirable to provide a flow restrictor (notshown) between the accumulator and the planetary unit to reduce thelikelihood of excessive speeds during the shift process.

When used with a CVT that does not incorporate centrifugal pressurecompensation, the pressures in the cylinders 140, 142 are only naturallybalanced when the sheaves 110, 112 are operating at near the same speed,or at a one to one ratio. The greatest imbalance is at the ratioextremes. For example, in the highest ratio (low gear), the primarycylinder 140 generates an increased internal pressure because of itshigher speed than the secondary cylinder 142 because of the centrifugalforce and visa-versa at the lowest ratio. This imbalance during aninitial acceleration increases with sheave speed and can initiate apremature ratio change. To adjust to such a ratio change, the driver canmove the lever 401 to the high ratio position (i.e., low gear) to createa higher observed pressure to the secondary cylinder 142. Once theengine speed reaches a desired level, the driver can allow a ratiochange to start by reducing the bias through the lever 401 until a ratechange is observed. By manipulation of the lever 401, the driver cancontrol the rate change until overdrive is reached with the lever 401 inthe low ratio position (i.e., high gear) or anywhere in between asdesired. Such manipulation is similar to the use of a stick shift.

With the lever 401 in a maximum stroke in either direction (i.e., lowgear position or high gear position), the cylinders 140, 142 will reachfull stroke. With the cylinders 140, 142 at full stroke, cylinder tocylinder flow will substantially cease, which causes a hydraulic lockand can stall the pump 126 and the motor 122. Accordingly, a bypassrelief valve 410 can be inserted to recirculate flow back to the pump126 when a preset differential high pressure is reached. In someconfigurations, the bypass relief valve 410 is a 100 psi relief valve.The preset differential high pressure preferably is enough to hold theCVT 104 in the overdrive range while the vehicle operates in a cruisemode.

In some configurations, a manually operated control knob 412 can beprovided to the bypass relief valve 410. The control knob (or handle)412 can be used to adjust the bypass pressure differential such thatshifting of the CVT 104 can be more finely adjusted, such as through avernier (i.e., a more precise manner of adjusting the ratio than simplyusing the four way valve lever only).

Under normal acceleration of the associated vehicle, the four way valvehandle 401 initially can be set in the low range position. As the speedincreases, the driver can incrementally rotate the handle 401 to causethe ratio to change and eventually reach the high range or overdriveposition. At this point, cylinder to cylinder flow will cease and thebypass relief valve 410 will recirculate the pump flow back to the pump126. The pressure setting of the bypass relief valve 410 preferably isenough to hold the CVT ratio in a high range during normal cruise mode.

When passing or hill climbing, as well as other situations that theratio is changed into a lower range by a small amount and with moreprecise control than can be achieved by the handle 401 of the four wayvalve 400, the four way valve handle 401 is left in the high rangeposition but the differential pressure between the cylinders can bereduced with the control knob 412 of the bypass relief valve 410. Thesetting of the bypass relief valve 410 can be used to initiate a changeand then can set the pressure to hold the desired ratio. The knob 412 ofthe bypass relief valve 410 can be returned to its highest pressuresetting upon resumption of cruise mode.

In some applications, an instrument control panel (not shown) can show aroad speed, an engine speed, CVT cylinder pressures and a sensed CVTratio, for example. Such data can be used to help a driver efficientlycontrol the CVT 104. Other configurations are possible. In someapplications, the CVT ratio can be sensed with the use of potentiometersand volt meters, or the like.

In addition to the simplified control systems described above, someaspects of the present invention result in a modular construction thatsimplifies manufacturing and maintenance in the field. Moreover, byvirtually removing all electronics from the device, no sophisticateddiagnostic equipment is needed for trouble shooting. As noted above, insome configurations, a single 12 volt direct current motor drives a pumpat each end. In some embodiments, the high pressure line from the pumpis connected to the primary sheave leg of the cylinder pressurizing lineto assure substantially full clamping pressure at the primary sheave atall times. Further, separate cooling and lube pumps are not needed whilepositive, separate lubrication can be provided to both the CVT flexiblemember and the planetary gear set.

While the arrangement described above is manually operated and generallydoes not require sensors and supporting electronics, it is possible thatthe basic system, as described above, need not be only manuallyoperated. The manually operated handle 401 of the four way valve 400,for example, can be replaced by an actuator, such as a stepper motor,for example but without limitation. The stepper motor can automate theshift function for the CVT 104. In other words, the actuator canautomatically manipulate the four way valve 400.

In some configurations, signal inputs can be obtained that represent anengine output speed (i.e., the speed of the transmission input shaft), aspeed of the transmission output shaft 116, a CVT ratio position and athrottle position. These signals can be obtained from any suitablesensors. The signals can be provided to an electronic motion controllerthat integrates and processes the signals in accordance with suitableprogramming. The output of the motion controller then is connected to anelectronic step motor drive that controls the positioning of the stepmotor and the hydraulic four way valve. In some configurations: the stepmotor is part number HT17-075, available from Applied Motion Products;the step motor drive is part number 1240i, also available from AppliedMotion Products; the motion controller is part number P192, availablefrom Trio Motion Technology; the input shaft speed sensor and the outputshaft speed sensor are part number MP37TA, available from Red Lion; theratio indicator is part number Linear Potentiometer 520173, availablefrom ELAP; and the throttle position sensor is part number 657-0-0-502,available from Vishay Potentiometer.

In some configurations, the shaft speed sensors are magnetic pulsegenerators that can be located at shaft ends of the CVT. Such generatorsproduce electric pulses 16 times per revolution. The linear transducerpreferably follows the position of the moving primary sheave half andchanges resistance as the drive ratio changes. Finally, the throttleposition sensor can be directly connected to the throttle and can changeresistance as the pedal moves. Other configurations also are possible.

FIG. 5 illustrates another CVT system control 500 that is arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention. As with the CVT system control 100 describedabove and shown in FIG. 1, the CVT system control 500 provides asimplified and preferably substantially electronic free method ofpressurizing and providing variable pressure control of a hydraulicsystem in a belt or chain drive continuously variable transmission. Inthe illustrated system control 500, two separate functions arecontrolled: chain clamping and cylinder pressure manipulation. Thecylinder pressure manipulation changes CVT engine/drive line ratios whenfluid passes from in either direction between cylinders. Rather thanfully describe the components that remain generally the same between theCVT system control 100 of FIG. 1 and the CVT system control 500 of FIG.5, the main differences will be described.

As illustrated in FIG. 5, the CVT system control 500 preferably has aseparate module that supplies lubricant to the flexible transmitter 114and the planetary transmission 120. The illustrated module comprises amotor 502. The motor 502 receives power from the power source 130, whichwas described above. Other configurations are possible.

The motor 502 drives a pump 504. The pump 504 can be any suitable pump,including those described above with respect to the pumps 124, 126. Thepump 504 draws fluid from the reservoir 132. From the reservoir 132, thepump 504 feeds the fluid through a heat exchanger 506. From the heatexchanger 506, the fluid is used to lubricate the flexible transmitter114 and is supplied to the planetary transmission 120 to lubricate themoving components of the planetary transmission 120. Thus, the coolingcircuit can be split between the CVT chain and the planetary mechanism.This system preferably only operates at about 10 psi.

Thus, the construction of FIG. 5 differs from the construction of FIG. 1primarily in the provision of a separate lubricant pump and motor (seeFIG. 5) rather than using bypass flow and case drain flow to provide thedesired lubrication (see FIG. 1). Given this primary difference, twoother changes also can be found between FIG. 5 and FIG. 1. Namely, thepressure modulating relief valve 144 recirculates back to the first pump124 without bypassing a flow for lubrication purposes and the secondpump 126 does not use the case drain to lubricate the gears of theplanetary transmission. Otherwise, the construction of FIG. 5 is largelythe same as the construction illustrated in FIG. 1.

FIG. 6 illustrates another CVT system control 600 that is arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention and FIG. 7 illustrates a further CVT systemcontrol 600 that is arranged and configured in accordance with certainfeatures, aspects and advantages of the present invention. As with theCVT system control 500 described above and shown in FIG. 5, the CVTsystem controls 600 and 700 provide simplified and preferablysubstantially electronic free methods of pressurizing and providingvariable pressure control of a hydraulic system in a belt or chain drivecontinuously variable transmission. In the illustrated system controls600, 700, two separate functions are controlled: chain clamping andcylinder pressure manipulation. The cylinder pressure manipulationchanges CVT engine/drive line ratios when fluid passes from in eitherdirection between cylinders. Rather than fully describe the componentsthat remain generally the same between the CVT system control 500 ofFIG. 5 and respectively the CVT system control 600 of FIG. 6 and the CVTsystem control of FIG. 7, the main differences will be described.

The CVT system control 600 of FIG. 6 differs from the CVT system control500 of FIG. 5 primarily in two regards. First, rather than driving thefirst and second pumps 124, 126 from a single motor 122 (shown in FIG.5), the CVT system control 600 of FIG. 6 uses a first motor 602 to drivea first pump 604 and a second motor 606 to drive a second pump 610. Bothmotors 602, 606 can be powered by the same power source 130.

The first pump 604 can be a variable displacement/variable pressurehydraulic pump of vane or other type, which draws oil from the reservoir132. The oil is directed under pressure to the passage 136 that connectstogether the primary and secondary cylinders 140, 142 of the CVT 104,similar to that described above, to establish the clamping force forboth sheaves 110, 112 and for other functions. The first pump 604preferably can vary the output flow and pressure through a pressuremodulating actuator 605. In some embodiments, a spring loaded pressuresetting can be changed according to the clamping force desired. Thebypass relief valve shown in FIG. 1 and FIG. 5 is eliminated in thesystem 600 of FIG. 6 and is no longer a source of energy loss and heatgeneration.

The CVT system control 700 of FIG. 7 differs from the CVT system control500 of FIG. 5 primarily in two regards. First, rather than driving thefirst and second pumps 124, 126 from a single motor 122 (shown in FIG.5), the CVT system control 700 of FIG. 7 uses a first motor 702 to drivea first pump 704 and a second motor 706 to drive a second pump 710. Bothmotors 702, 706 can be powered by the same power source 130 following aconversion to 115 volts AC by a converter 712. Other configurations arepossible.

Although the present invention has been disclosed in the context ofcertain preferred embodiments, examples and variations, it will beunderstood by those skilled in the art that the present inventionextends beyond the specifically disclosed embodiments to otheralternative embodiments and/or uses of the invention and obviousmodifications and equivalents thereof. For example, in the event ofserial production requirements all of the system components can beredesigned/combined etc. for cost effective results. In addition, whilea number of variations of the invention have been shown and described indetail, other modifications, which are within the scope of thisinvention, will be readily apparent to those of skill in the art basedupon this disclosure. It is specifically contemplated that variouscombinations or subcombinations of the specific features and aspects ofthe embodiments may be made and still fall within the scope of theinvention. It should be understood that various features and aspects ofthe disclosed embodiments can be combined with or substituted for oneanother in order to form varying modes of the disclosed invention.Moreover, some variations that have been described with respect to oneembodiment and not another embodiment can be used with such otherembodiments. Many other variations also have been described herein andcross-application is intended where physically possible. Thus, it isintended that the scope of the present invention herein disclosed shouldnot be limited by the particular disclosed embodiments described above,but should be determined only by a fair reading of the claims thatfollow.

1. A transmission and transmission control comprising: a continuouslyvariable transmission comprising a first sheave and a second sheave, aflexible member connecting the second sheave to the first sheave suchthat rotation of the first sheave causes rotation of the second sheave,a continuously variable transmission output shaft being connected to thesecond sheave; a planetary transmission comprising an input shaft, theinput shaft of the planetary transmission being connected for rotationwith the continuously variable transmission output shaft, the planetarytransmission input shaft being connected to a planetary transmissionoutput shaft; a motor driving a first pump and a second pump; the firstpump being fluidly connected to the first sheave and the second sheave,the first pump also being fluidly connected to a pressure relief valve,the pressure relief valve being connected to a flexible memberlubrication conduit such that bypass flow from the pressure relief valvecan be directed to the flexible member of the continuously variabletransmission; and the second pump being fluidly connected to a valve,the valve being selectively fluidly connected to the first sheave andthe second sheave such that fluid can be supplied through the valve tothe first and second sheave to effect ratio changes, the second pumpcomprising a pump case drain, the pump case drain being fluidlyconnected to the planetary transmission to supply fluid to gears of theplanetary transmission.
 2. The transmission and transmission control ofclaim 1, wherein the first pump draws fluid from a reservoir.
 3. Thetransmission and transmission control of claim 2, wherein the first pumpdraws fluid from the reservoir through a heat exchanger.
 4. Thetransmission and transmission control of claim 1, wherein the first pumpcomprises a pump case drain and the pump case drain is fluidly connectedto the flexible member lubrication conduit such that fluid from the pumpcase drain can be directed to the flexible member of the continuouslyvariable transmission.
 5. The transmission and transmission control ofclaim 1, wherein a bypass relief valve is fluidly connected to thesecond pump, the bypass relief valve selectively bypassing fluid aroundthe valve back to the second pump.
 6. The transmission and transmissioncontrol of claim 5, wherein the bypass relief valve comprises a knob,the knob being arranged and configured to adjust a pressure level atwhich bypass flow occurs.
 7. The transmission and transmission controlof claim 1, wherein the bypass relief valve that is connected to thefirst pump comprises an inlet passage, the inlet passage being fluidlyconnected to a bypass passage, a valve seat and a valve member beingpositioned between the inlet passage and the bypass passage, and thevalve member being biased with a biasing force toward the valve seat bya biasing member.
 8. The transmission and transmission control of claim7, wherein the bypass relief valve further comprises an adjustmentportion, the adjustment portion altering the biasing force based uponoperator engine demand.
 9. The transmission and transmission control ofclaim 8, wherein the adjustment portion comprises a chamber, a diaphragmdividing the chamber into a first portion and a second portion, thefirst portion being fluidly connected to ambient pressure and the secondportion being fluidly connected to an engine intake pressure, thediaphragm being connected to the valve member such that movement of thediaphragm toward the second portion results in increased bypass flow.10. The transmission and transmission control of claim 8, wherein theadjustment portion comprises an input member, the input member receivinginput indicative of increased operator demand on the engine, the inputmember being connected to the valve member such that increased operatordemand on the engine results in decreased bypass flow.
 11. Thetransmission and transmission control of claim 8, wherein the adjustmentportion comprises an input member, the input member moving toward thevalve seat when operator demand on the engine increases.
 12. Thetransmission and transmission control of claim 11, wherein a bushing isinterposed between the input member and the valve member, the bushingtransferring forces from the input member to the valve member.
 13. Thetransmission and transmission control of claim 12, wherein a spring isinterposed between the input member and the bushing such that force fromthe input member is transferred to the bushing through the spring. 14.The transmission of claim 11, wherein the adjustment portion comprises astop, the stop limiting a range of movement of the input member.
 15. Atransmission and transmission control comprising: a continuouslyvariable transmission comprising a first sheave and a second sheave, aflexible member connecting the second sheave to the first sheave suchthat rotation of the first sheave causes rotation of the second sheave,a continuously variable transmission output shaft being connected to thesecond sheave; a planetary transmission comprising an input shaft, theinput shaft of the planetary transmission being connected for rotationwith the continuously variable transmission output shaft, the planetarytransmission input shaft being connected to a planetary transmissionoutput shaft; a first pump supplying fluid to the first sheave and thesecond sheave such that the first pump creates a base clamping pressure,means for modulating pressure according to engine demand being connectedto the first pump such that increased operator demand on an engineresults in higher clamping pressures being applied to the first andsecond sheave; and a second pump fluidly connected to a valve, the valveselectively supplying fluid to at least one of the first and secondsheaves to effect ratio changes between the first and second sheaves.